I don’t quite understand what you’re inquiring about. Maybe it’s the ranging principle of the S2?
The RPLIDAR S2 is based on laser flight-of-time (TOF) ranging principle and adopts the high-speed laser acquisition and processing hardware developed by SLAMTEC. The system ranges more than 32000 times per second. During every ranging process, the RPLIDAR emits modulated infrared laser signal and the laser signal is then reflected by the object to be detected. The returning signal is then sampled by laser acquisition system in RPLIDAR and the processor embedded in RPLIDAR starts processing the sample data and outputs distance Range Scanner Core value and angle value between object and RPLIDAR S2 via communication interface.